&Expr(ParExpr{
    expr: Expr(InfixExpr{
        left: Expr(InfixExpr{
            left: unknown sum type value
            right: unknown sum type value
        })
        right: Expr(InfixExpr{
            left: unknown sum type value
            right: unknown sum type value
        })
    })
})
&Expr(ParExpr{
    expr: Expr(InfixExpr{
        left: Expr(InfixExpr{
            left: unknown sum type value
            right: unknown sum type value
        })
        right: Expr(InfixExpr{
            left: unknown sum type value
            right: unknown sum type value
        })
    })
})
&Expr(InfixExpr{
    left: Expr(InfixExpr{
        left: unknown sum type value
        right: unknown sum type value
    })
    right: Expr(InfixExpr{
        left: unknown sum type value
        right: unknown sum type value
    })
})
&Expr(InfixExpr{
    left: Expr(InfixExpr{
        left: unknown sum type value
        right: unknown sum type value
    })
    right: Expr(InfixExpr{
        left: unknown sum type value
        right: unknown sum type value
    })
})
